2004 civic ex wont rev past 4k
#1
2004 civic ex wont rev past 4k
I just got this civic and the check engine like is on and it was a rocker arm code and 02 sensor. but now its just the 02 sensor, it wont rev past 4k in neutral or in any gear. its weird though bc when i first start it its fine i can rev it wide open but before im too the end of my rode it does it again. ive read alot about this problem and know alot about hondas but im in need of some help. ive ran gumout and seafoam, i just got an oil change today, ive reset of ecu. ive cleaned the vtec seloniod gasket, i have no power issues so im confident it isnt my ecu or bad connection anywhere or grounded wrong. it does have a swapped engine just another d17a2 like original motor (previous owner blew 1st motor). motor only has 50k on it. please help!?!?
#2
Honda-Tech Member
Join Date: Jan 2013
Location: Sussex, NJ
Posts: 71
Likes: 0
Received 0 Likes
on
0 Posts
Re: 2004 civic ex wont rev past 4k
I'd start looking at fuel pressure and exhaust back pressure. If you have a fuel pump issue, that could cause it. Hondas have been traditionally sensitive to alcohol in the fuel. with today's ethanol blends, it is possible you could have a weak fuel pump.
If you have low vacuum, it might mean a clogged cat. You can monitor vacuum either with a gauge or with an OBD II scanner. Look at MAP kPa. It should be around 30 at idle and 99 at WOT. If the idle numbers are higher than 32 (I've seen them range from 29 to 31 at 700' elevation), you may have cat issues.
Of course there are about 500 other things you could check, but at least this is a start.
Mike
If you have low vacuum, it might mean a clogged cat. You can monitor vacuum either with a gauge or with an OBD II scanner. Look at MAP kPa. It should be around 30 at idle and 99 at WOT. If the idle numbers are higher than 32 (I've seen them range from 29 to 31 at 700' elevation), you may have cat issues.
Of course there are about 500 other things you could check, but at least this is a start.
Mike
Thread
Thread Starter
Forum
Replies
Last Post